The research involves studies of capillary phenomena applicable to the behavior of liquids at the sites of caries susceptibility. Liquids trapped in isolated contact with solids undergo major changes in internal pressure which affect their properties. The effects of isolated capillary action on surface tension and adsorption from solution will be studied. The capillary penetration coefficient of pit and fissure sealants will be developed as a selection criterion. Hydrophobic coatings which may be capable of reducing capillary action and the adhesion of plaque will be studied. The solubility of crystal apatites in liquids held in minute capillary spaces will be measured.